<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>js引入</title>
  <script src="demo.js"></script>

<!--  <script>-->
<!--    alert('hello world');-->
<!--  </script>-->
</head>
<body>
<div></div>
<script>
  document.write('今天星期二');
</script>
<script>
  console.log('现在是9.35');
</script>

<!--<script>-->
<!--  alert('hello body');-->
<!--</script>-->
</body>
</html>